1. Field of the Disclosure The present disclosure relates to obtaining a parameter of interest in a swept-wavelength interferometry systems for use in wellbores.
2. Description of the Related Art
In various aspects of oil exploration and production, optical sensors are deployed downhole and a light source at a surface location supplies light to the optical sensors over a fiber optic cable. Light interacts with the optical sensors to produce a reflected light having a signal that is returned to the surface to be measured. Typically, the returned light is sampled at a sampling device which is controlled using a trigger signal obtained from a suitable source, such as the light source. When sampling signals, a sampling frequency is generally selected that prevents false reconstruction of the original signal, a process known as aliasing. The highest signal frequency that can be successfully reconstructed for a selected sampling frequency is known as the Nyquist frequency. Some systems currently in use include anti-aliasing filters that remove signals above a selected fixed cut-off frequency of the filter. However, if the signal frequency is changing, as in swept-wavelength systems, such filters may be inadequate. The need to design systems to prevent signal aliasing introduces factors that constrain the utility of the system, or can reduce data fidelity. The present disclosure therefore provides a method and apparatus for moderating these constraints and/or improving the data fidelity in swept-wavelength systems.